A primary focus of the Koch Institute?s research program is to understand the molecular and cellular changes associated with cancer development and progression and develop new treatments and diagnostic approaches. The Microscopy Core provides state-of-the-art imaging in both cells and in the in vivo setting, which are essential tools for these studies. In the current period, the capabilities of this Core have been expanded and enhanced. This includes: moving into a larger, custom-designed space in the new Koch Institute building; the acquisition of new instrumentation; and the recruitment of a world-renowned expert in intravital imaging, Jeffrey Wyckoff, to the Core?s staff. Notably, in the same period, 78% of Center Members used the Microscopy Core, including investigators from all four Programs. Thus, this Shared Resource is essential to the success of the Koch Institute mission. In the upcoming period, this Core will continue to offer a wide range of state-of-the-art imaging technologies to support the research programs of Center Members. To support its expanded staff, the requested budget for Year 44 is increased 45%, compared to the requested and recommended budget in Year 39. The CCSG budgets of other Koch Institute Cores have been reduced or eliminated to more than offset the proposed increase in this, and other, Cores.